The present invention relates generally to a chain saw bar system, such as may be used on tree harvesters, and more particularly to an improved selectable spray pattern chain saw bar system, including an improved saw bar for applying a predetermined fluid pattern, an improved harvester, and an improved method of applying a predetermined pattern of fluid on surface formed by cutting during the cutting step. The improved saw bar, harvester and method of the present invention may be used to spray a rot preventing agent, such as urea, on tree stumps when felling trees, or to selectably spray a predetermined paint pattern on an end of a log formed by cutting during log bucking, with the paint pattern selected designating various log characteristics or other identifiers.
Other saw bar systems have been proposed for spraying urea on a tree stump during the tree felling process. For instance, U.S. Pat. No. 5,050,303 to Sinclair et al. discloses a chain saw bar fluid passage system having a saw bar which sprays urea therefrom onto the stump of a felled tree. However, Sinclair et al. is limited to dispensing fluid from a single side of the saw bar. Furthermore, the Sinclair et al. saw bar has no manner of controlling the flow of urea spray therethrough, leading to large amounts of urea being wasted when cutting small diameter trees.
Other systems have been used for color marking the ends of logs to designate various characteristics of the log, such as for scaling of length, diameter or for other identification purposes. For example, U.S. Pat. No. 4,169,173 to Bergholm et al. discloses a method of color marking the ends of logs which have previously been cut to predetermined lengths. Bergholm et al. requires the logs to first be severed from their stumps and then transported to the cutting and marking processor. Bergholm et al. is limited to color coding the logs in a separate step after the log has been completely severed.
Tree harvesting machines or harvesters typically have large tractor-mounted feller heads or harvester heads for cutting timber. Some harvesters use large chain saw bars with an endless cutting chain which is swept horizontally through a tree to sever it from the remaining stump. One such tree harvester is disclosed in U.S. patent application Ser. No. 07/691,749, filed on Apr. 25, 1991, and invented by Mack, which is herein incorporated by reference for the teachings and disclosure provided therein. The Mack invention and the invention claimed herein are each owned by a common assignee, Blount, Inc.
The Mack harvester has an onboard computer which receives diameter and length signals from respective diameter and length transducers on the harvester head. The Mack computer uses the length and diameter signals, along with other operator-input signals, to grade logs cut by the Mack harvester. The Mack computer also provides a grade indication signal to a color selector circuit which controls the flow of varying colors of paint to a spray nozzle. The nozzle is solenoid actuated to spray paint only after the log has been cut and the chain saw returns to a rest position so the saw bar will not be sprayed by the paint.
Thus, a need exists for an improved selectable spray pattern chain saw bar system, including an improved saw bar for applying a predetermined fluid pattern, an improved harvester, and an improved method of applying a predetermined pattern on surface formed by cutting during the cutting step, which are directed toward overcoming, and not susceptible to, the above limitations and disadvantages.